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Topic Review (Newest First)

05-09-2012 06:38 PM

rollie715

Quote:

Originally Posted by louis165

Have you checked the block to make sure it is set up for a roller cam ? I have a 90 truck block and it wasn't a roller block

Yes, the dogbone area is machined, the front camshaft retainer surface and holes are drilled and tapped, and it has risers where the spider would mount. The only thing I can see that it needs is to drill and tap the spider mounting risers. I have a spider and dog bones and they fit correctly in place. I think I posted a couple pics of those areas in an earlier post on this same thread.

Here's the pics again:
Poor pic but shows area.

05-09-2012 06:32 PM

louis165

Have you checked the block to make sure it is set up for a roller cam ? I have a 90 truck block and it wasn't a roller block

05-09-2012 10:01 AM

ap72

I know its too late, but in the future you can get the spider, retainers, lifters, and pushrods from a JY for about $25. It would have saved you a few hundred dollars. Also, ls2 valvesprings would have been more than adequate, which would have also saved you about a hundred bucks.

I don't know if you're open to using used parts but your build could have been done for about a third of the cost and made the same power, something to keep in mind down the road.

05-09-2012 09:12 AM

rollie715

After lots of reading on the internet, I am getting very close to a plan for my engine build. Many of you on this site have influenced and taught me (I don't want to name names, as I will miss someone), as well as people on other sites, particularly a member of clubhotrod.com named techinspector1.

Here's a thread he commented on that just about fits my my own build:355 Daily Driver

Just to repeat myself, my goal is a mild, good idling, good mileage, daily driver, runs cheap gas, good low end torque pushing an auto tranny.
So far this looks like a 9:1 compression, 350+hp, 450+torque

The shopping has begun! So far I have purchased the following: (just hope it will all work together)

Comp Cam 08-410-8 build 260HR camshaft, Magnum series, very mild, should be gentle on valve train, new from private party on Ebay, Price $220

Edelbrock 2716 Performer EPS Vortec intake manifold, cast finish, I chose EPS over RPM, as I wanted low end torque and not high rpm, US Parts on Ebay, Price $188

Items I haven't purchased yet, but am really close to are:

Pistons, D shaped dish with good flat area in the quench area, about 18cc dish to reach my intended CR of 9:1. Considering the Keith Black KB142.

Head gasket, Felpro Q1003 .041 compressed (requires a 9.000 deck), or GM 10105117 .028 which may be a better choice as it would likely fit better with a 9.013 deck height and .040 squish.

Connecting Rods, 5.7", should I reuse original or buy new?

Headers, Full length 1-5/8 to 3-bolt 3" collector. Not sure of best route, but considering the cheap ones from Summit, Price $110

Your comments are always welcome, as I am making this up as I go from what I learn.

04-28-2012 09:09 PM

rollie715

I attended a swap meet in Mt Vernon Wa today where I picked up a nice set of used 906 Vortec heads. Here's a close up of one of the combustion chambers:

Here's a shot of some pistons I'm thinking of getting:

Notice the similarities between the head combustion chamber shape and the top of the piston. My theory is since I need to lower the compression ratio a little I will need some kind of dished pistons. This particular one looks like a cross between a D-Dish with valve reliefs and a flat top in the area where the corrosponding flat area is in the head. My theory is that the larger the flat area where the quenching occurs the better it will function and that the dished area below the head chamber is the right place to add the extra cc's and still ressemble an efficient chamber.

This particular piston, the Keith Black KB193-030 (assuming a 0.030 oversize bore) as found at Summit at : KB193 Pistons has a 12cc dish which when blocked decked for a 0.040 quench assuming 67cc measured head gives me a static compression ratio of 9.32 and with a cam advertised Intake Closing timing Angle of 56 which is common for many of the mild cams I've been looking at results in a dynamic compression ratio of 7.93 which according to what I've been reading is right in the ballpark for where I want to be when running regular 87 octane gas.

I think I'm getting close to a workable combination.

I plan to do a cc check on the heads for final calculations, and probably deck the block after dry assembling the parts to get precise piston to deck height measurements. Also will likely need to work the heads a little to increase the valve lift limits.

I've been reviewing various camshafts, but still have a ways to go, to understand all the options. Ideally I want an efficient mix of low end torque and mileage.

From what I see so far, I'm guessing this engine should produce horsepower in the mid 300's at around 4500rpm and torque in the mid 400's at about 3500rpm.

Still a ways to got, but I think I'm making progress and enjoying the entire journey. Thanks again for all your input. It is really helping me.

04-22-2012 02:51 AM

cobalt327

eBay usually has vendors selling the spiders and dog bones. You'll also need a cam retainer plate to match your block, it's held on w/button head screws for clearance. There were two different widths of cam retainers so get the right one to match your block. If your block isn't drilled for the retainer, either retainer will work.

Push rods are about 7.2" long for the hydro roller, FT cams used a push rod about 7.8" long. The exact length will be decided after you mock up the engine using the cam, heads, valves, head gaskets, rockers, rocker studs, etc. you intend to run.

I hope you don't mind if I just keep adding more to this thread. As the name implies, I hope to document my research and build of my Vortec 350.

Just in case you you haven't been following all of my thread, I have a 350TBI out of an 89 1500 pickup, that I plan to rebuild and turn into a carburated Vortec engine. Today I started stripping it down. I believe this motor was originally a flat tappet design, but was built on a block that could easily be converted to roller tappets. Here's a couple pics of the area where a spider and lifter guides(I'm not exactly sure what they are called) would be. It looks to me like the guide area is already machined, but the spider mounting risers need to be drilled and tapped, a job which I should be able to do easily. Can someone familiar with the machined guide area, confirm that my block is machined ready for the roller lifter guides?

Here's a closeup of the machined guide area.

The next question, is where would be an easy and cheap place to buy a spider and guides?

I'm also guessing that judging by how deep the existing lifters sit down inside their holes, that a new set of roller lifters will stick up higher into the guides and require a different set of shorter push rods.

04-20-2012 11:18 PM

cobalt327

Quote:

Originally Posted by rollie715

I think the Summit site was showing the wrong picture. Upon googling the part number I found this picture which might be a more correct photo: Quench area looks much better in my opinion.

I'm wondering with a 10cc dish, if this picture could be right with the valve reliefs taking up most of the volume. The picture shows a flat top in the quench area, but only 2 valve reliefs.

04-20-2012 09:22 PM

cobalt327

Quote:

Originally Posted by rollie715

Not stuck, just trying to learn this new myself. I just keep modifying what I think I know as I learn more.

Thank you

The Vortec head has an excellent combustion chamber shape, you do not want to alter that, but there are ways to add volume to it w/o disrupting the chamber's function.

So if you want to use a FT, research reworking the combustion chambers to gain volume and see if it's something you think you can handle. You'll need grinding tools, and eye protection, and a good amount of spare time. It can be done w/nothing more specialized than a Dremel, sanding rolls and bits, a pair of goggles and a way to measure the chamber volume accurately as you work. You'll never want to do it twice, it's a dirty time consuming job. But it is an option, although getting 12cc more volume w/o running into problems might be impractical if not impossible.

I believe you ought to build this engine right. That may well mean spending more than a ten spot on a piston. If you want cheap, then so be it.

04-20-2012 03:30 PM

rollie715

Quote:

Originally Posted by Silver Surfer

Why are you stuck on the d-dish?.

Not stuck, just trying to learn this new myself. I just keep modifying what I think I know as I learn more.

Thank you

04-20-2012 03:16 PM

Silver Surfer

For quench in order of best to worst piston design:
flat top no valve relief
flat top 2 valve reliefs
flat top 4 valve reliefs
D-Dish
Dish and dome (not sure which is better than the other)

Why are you stuck on the d-dish? I would do everything I could with manipulating deck clearance, piston compression height and head gasket thickness so I could stick with flat tops.

04-20-2012 02:25 PM

rollie715

Quote:

Originally Posted by Silver Surfer

What are your horsepower goals, street manner goals (low end, high end power, torque, loping idle)? That will narrow down your cam selection, and that will determine your compression ratio. Then tear down and inspect your engine, then machine work, then parts selection to get your compression ratio and squish.

Very good question.
Originally before I did any research I threw out a ballpark goal of 300hp, 400torque, slight lopey idle, 15mpg in 3500lb Camaro.
700r4 tranny, with appropriate rear end ratio.
Daily driver, Street use only, Good low end torque, Strong launch from a standing start, Spin tires when desired, good street manners for normal driving. No desire to wind it up to high rpm.

Initial feedback suggested a fuel injected engine, but since then I'm leaning back to using a carb. At this point I'm thinking of an L31 or 350HO as a base, but with slight improvements, which would put me in the mid 300's for power and 380-420torque.

On the subject of piston top design for good quench. Realizing that I will probably need some kind of dish, it seems the best design is the D shape where the flat top matches up with the flat portion of the head for maximum quench area. Here's the two styles suggested above available from Summit for a good price. Neither one is a tru D shaped dish.

SLP-H423ACP60

SLP-WH423NP

04-20-2012 01:23 PM

Silver Surfer

Quote:

Originally Posted by rollie715

Thanks again,

The last few posts have been the most helpful so far. I started this new thread because a previous thread ended up with lots of book chapters between differing views.

At this point, my next step is to tear down my motor and see what I have to work with. Then I will get back to the detailed specs needed.

The piston combinations and recent comments on cam overlap and dynamic compression has been encouraging.

I will add updates as I know more.

By the way, I'm planning un using a carb and not the fuel injection or computer.

What are your horsepower goals, street manner goals (low end, high end power, torque, loping idle)? That will narrow down your cam selection, and that will determine your compression ratio. Then tear down and inspect your engine, then machine work, then parts selection to get your compression ratio and squish.

04-20-2012 01:20 PM

Silver Surfer

Quote:

Originally Posted by cobalt327

That's why block decking to ensure HG seal was accounted for in the figures I supplied. Flatness, while a requirement, is only half the equation- the surface finish is also important if using shim head gaskets. Coated shim gaskets are a little more forgiving but will still seal best w/the correct finish.

Had I also been discussing CR in that post (it was about quench, primarily), I would have said that milling the heads, while not affecting the quench, WILL slightly raise the CR. But I wasn't, so I didn't. Have to draw the line somewhere, lest the post turn into a freaking book. Like this one is fixing to do.

My bad, I misread your post

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